package com.jdy.haoduoaiteacher.scan.camera;

/*
 * Copyright (C) 2008 ZXing authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import android.content.Context;
import android.graphics.PixelFormat;
import android.graphics.Point;
import android.graphics.Rect;
import android.hardware.Camera;
import android.os.Build;
import android.os.Handler;
import android.util.Log;
import android.view.SurfaceHolder;

import com.jdy.haoduoaiteacher.util.Tools;

import java.io.IOException;

/**
 * This object wraps the Camera service object and expects to be the only one
 * talking to it. The implementation encapsulates the steps needed to take
 * preview-sized images, which are used for both preview and decoding.
 * 
 */
public final class CameraManager {

  private static final String TAG = CameraManager.class.getSimpleName();

  private static final int MIN_FRAME_WIDTH = 240;
  private static final int MIN_FRAME_HEIGHT = 240;
  private static final int MAX_FRAME_WIDTH = 480;
  private static final int MAX_FRAME_HEIGHT = 360;

  private static CameraManager cameraManager;

  static final int SDK_INT; // Later we can use Build.VERSION.SDK_INT
  static {
    int sdkInt;
    try {
      sdkInt = Integer.parseInt(Build.VERSION.SDK);
    } catch (NumberFormatException nfe) {
      // Just to be safe
      sdkInt = 10000;
    }
    SDK_INT = sdkInt;
  }

  private final Context context;
  private final CameraConfigurationManager configManager;
  private Camera camera;
  private final Rect framingRect = new Rect();
  private Rect framingRectInPreview;
  private boolean initialized;
  private boolean previewing;
  private final boolean useOneShotPreviewCallback;
  /**
   * Preview frames are delivered here, which we pass on to the registered
   * handler. Make sure to clear the handler so it will only receive one
   * message.
   */
  private final PreviewCallback previewCallback;
  /**
   * Autofocus callbacks arrive here, and are dispatched to the Handler which
   * requested them.
   */
  private final AutoFocusCallback autoFocusCallback;

  /**
   * Initializes this static object with the Context of the calling Activity.
   * 
   * @param context
   *          The Activity which wants to use the camera.
   */
  public static void init(Context context) {
    if (cameraManager == null) {
      cameraManager = new CameraManager(context);
    }
  }

  /**
   * Gets the CameraManager singleton instance.
   * 
   * @return A reference to the CameraManager singleton.
   */
  public static CameraManager get() {
    return cameraManager;
  }

  private CameraManager(Context context) {

    this.context = context;
    this.configManager = new CameraConfigurationManager(context);

    // Camera.setOneShotPreviewCallback() has a race condition in Cupcake, so we
    // use the older
    // Camera.setPreviewCallback() on 1.5 and earlier. For Donut and later, we
    // need to use
    // the more efficient one shot callback, as the older one can swamp the
    // system and cause it
    // to run out of memory. We can't use SDK_INT because it was introduced in
    // the Donut SDK.
    // useOneShotPreviewCallback = Integer.parseInt(Build.VERSION.SDK) >
    // Build.VERSION_CODES.CUPCAKE;
    useOneShotPreviewCallback = Integer.parseInt(Build.VERSION.SDK) > 3; // 3 =
                                                                         // Cupcake

    previewCallback = new PreviewCallback(configManager,
        useOneShotPreviewCallback);
    autoFocusCallback = new AutoFocusCallback();
  }

  /**
   * Opens the camera driver and initializes the hardware parameters.
   * 
   * @param holder
   *          The surface object which the camera will draw preview frames into.
   * @throws IOException
   *           Indicates the camera driver failed to open.
   */
  public void openDriver(SurfaceHolder holder) throws IOException {
    if (camera == null) {
      camera = Camera.open();
      if (camera == null) {
        throw new IOException();
      }
      camera.setPreviewDisplay(holder);

      if (!initialized) {
        initialized = true;
        configManager.initFromCameraParameters(camera);
      }
      configManager.setDesiredCameraParameters(camera);

      // FIXME
      // SharedPreferences prefs =
      // PreferenceManager.getDefaultSharedPreferences(context);
      // 是否使用前灯
      // if (prefs.getBoolean(PreferencesActivity.KEY_FRONT_LIGHT, false)) {
      // FlashlightManager.enableFlashlight();
      // }
      FlashlightManager.enableFlashlight();
    }
  }

  public void openDriver(SurfaceHolder holder, Camera c) throws IOException {
    if (camera == null) {
      camera = c;
      if (camera == null) {
        throw new IOException();
      }
      camera.setPreviewDisplay(holder);

      if (!initialized) {
        initialized = true;
        configManager.initFromCameraParameters(camera);
      }
      configManager.setDesiredCameraParameters(camera);

      // FIXME
      // SharedPreferences prefs =
      // PreferenceManager.getDefaultSharedPreferences(context);
      // 是否使用前灯
      // if (prefs.getBoolean(PreferencesActivity.KEY_FRONT_LIGHT, false)) {
      // FlashlightManager.enableFlashlight();
      // }
      FlashlightManager.enableFlashlight();
    }
  }

  /**
   * Closes the camera driver if still in use.
   */
  public void closeDriver() {
    if (camera != null) {
      FlashlightManager.disableFlashlight();
      camera.release();
      camera = null;
    }
  }

  /**
   * Asks the camera hardware to begin drawing preview frames to the screen.
   */
  public void startPreview() {
    if (camera != null && !previewing) {
      camera.startPreview();
      previewing = true;
    }
  }

  /**
   * Tells the camera to stop drawing preview frames.
   */
  public void stopPreview() {
    if (camera != null && previewing) {
      if (!useOneShotPreviewCallback) {
        camera.setPreviewCallback(null);
      }
      camera.stopPreview();
      previewCallback.setHandler(null, 0);
      autoFocusCallback.setHandler(null, 0);
      previewing = false;
    }
  }

  /**
   * A single preview frame will be returned to the handler supplied. The data
   * will arrive as byte[] in the message.obj field, with width and height
   * encoded as message.arg1 and message.arg2, respectively.
   * 
   * @param handler
   *          The handler to send the message to.
   * @param message
   *          The what field of the message to be sent.
   */
  public void requestPreviewFrame(Handler handler, int message) {
    if (camera != null && previewing) {
      previewCallback.setHandler(handler, message);
      if (useOneShotPreviewCallback) {
        camera.setOneShotPreviewCallback(previewCallback);
      } else {
        camera.setPreviewCallback(previewCallback);
      }
    }
  }

  /**
   * Asks the camera hardware to perform an autofocus.
   * 
   * @param handler
   *          The Handler to notify when the autofocus completes.
   * @param message
   *          The message to deliver.
   */
  public void requestAutoFocus(Handler handler, int message) {
    if (camera != null && previewing) {
      autoFocusCallback.setHandler(handler, message);
      // Log.d(TAG, "Requesting auto-focus callback");
      camera.autoFocus(autoFocusCallback);
    }
  }

  private static final double ratio = 0.65;

  /**
   * Calculates the framing rect which the UI should draw to show the user where
   * to place the barcode. This target helps with alignment as well as forces
   * the user to hold the device far enough away to ensure the image will be in
   * focus.
   * 
   * @return The rectangle to draw on screen in window coordinates.
   */
  public Rect getFramingRect() {
    // Point screenResolution = configManager.getScreenResolution();
    // if (framingRect == null) {
    // if (camera == null) {
    // return null;
    // }
    // int width = screenResolution.x * 3 / 4;
    // if (width < MIN_FRAME_WIDTH) {
    // width = MIN_FRAME_WIDTH;
    // } else if (width > MAX_FRAME_WIDTH) {
    // width = MAX_FRAME_WIDTH;
    // }
    // int height = screenResolution.y * 3 / 4;
    // if (height < MIN_FRAME_HEIGHT) {
    // height = MIN_FRAME_HEIGHT;
    // } else if (height > MAX_FRAME_HEIGHT) {
    // height = MAX_FRAME_HEIGHT;
    // }
    // int leftOffset = (screenResolution.x - width) / 2;
    // int topOffset = (screenResolution.y - height) / 2;
    // framingRect = new Rect(leftOffset, topOffset, leftOffset + width,
    // topOffset + height);
    // Log.d(TAG, "Calculated framing rect: " + framingRect);
    // }
    // return framingRect;

    Point screenResolution = configManager.getScreenResolution();
    if (framingRect == null || framingRect.isEmpty()) {
      if (camera == null) {
        return null;
      }
      // int width = screenResolution.x * 3 / 4;
      // if (width < MIN_FRAME_WIDTH) {
      // width = MIN_FRAME_WIDTH;
      // } else if (width > MAX_FRAME_WIDTH) {
      // width = MAX_FRAME_WIDTH;
      // }
      // int height = screenResolution.y * 3 / 4;
      // if (height < MIN_FRAME_HEIGHT) {
      // height = MIN_FRAME_HEIGHT;
      // } else if (height > MAX_FRAME_HEIGHT) {
      // height = MAX_FRAME_HEIGHT;
      // }
      int realHeight = Math.min(screenResolution.x, screenResolution.y);
      int width = (int) (realHeight * ratio);
      int height = (int) (realHeight * ratio);
      int leftOffset = (screenResolution.x - width) / 2;
      int topOffset = (screenResolution.y - height) / 2 - 50;
      framingRect.set(leftOffset, topOffset, leftOffset + width, topOffset
          + height);

      framingRect.top -= Tools.getPixelByDip(getContext(), 50);
      framingRect.bottom -= Tools.getPixelByDip(getContext(), 50);

      // framingRect = new Rect(leftOffset, topOffset, leftOffset + width,
      // topOffset + height);
      Log.d(TAG, "Calculated framing rect: " + framingRect);
      Log.d(TAG, "Calculated framing topOffset: " + topOffset);
    }
    return framingRect;
  }

  /**
   * Like {@link #getFramingRect} but coordinates are in terms of the preview
   * frame, not UI / screen.
   */
  public Rect getFramingRectInPreview() {
    if (framingRectInPreview == null) {
      Rect rect = new Rect(getFramingRect());
      Point cameraResolution = configManager.getCameraResolution();
      Point screenResolution = configManager.getScreenResolution();
      // modify here
      // rect.left = rect.left * cameraResolution.x / screenResolution.x;
      // rect.right = rect.right * cameraResolution.x / screenResolution.x;
      // rect.top = rect.top * cameraResolution.y / screenResolution.y;
      // rect.bottom = rect.bottom * cameraResolution.y / screenResolution.y;
      rect.left = rect.left * cameraResolution.y / screenResolution.x;
      rect.right = rect.right * cameraResolution.y / screenResolution.x;
      rect.top = rect.top * cameraResolution.x / screenResolution.y;
      rect.bottom = rect.bottom * cameraResolution.x / screenResolution.y;
      framingRectInPreview = rect;
    }
    return framingRectInPreview;
  }

  /**
   * Converts the result points from still resolution coordinates to screen
   * coordinates.
   * 
   * @param points
   *          The points returned by the Reader subclass through
   *          Result.getResultPoints().
   * @return An array of Points scaled to the size of the framing rect and
   *         offset appropriately so they can be drawn in screen coordinates.
   */
  /*
   * public Point[] convertResultPoints(ResultPoint[] points) { Rect frame =
   * getFramingRectInPreview(); int count = points.length; Point[] output = new
   * Point[count]; for (int x = 0; x < count; x++) { output[x] = new Point();
   * output[x].x = frame.left + (int) (points[x].getX() + 0.5f); output[x].y =
   * frame.top + (int) (points[x].getY() + 0.5f); } return output; }
   */

  /**
   * A factory method to build the appropriate LuminanceSource object based on
   * the format of the preview buffers, as described by Camera.Parameters.
   * 
   * @param data
   *          A preview frame.
   * @param width
   *          The width of the image.
   * @param height
   *          The height of the image.
   * @return A PlanarYUVLuminanceSource instance.
   */
  public PlanarYUVLuminanceSource buildLuminanceSource(byte[] data, int width,
      int height) {
    Rect rect = getFramingRectInPreview();
    int previewFormat = configManager.getPreviewFormat();
    String previewFormatString = configManager.getPreviewFormatString();
    switch (previewFormat) {
    // This is the standard Android format which all devices are REQUIRED to
    // support.
    // In theory, it's the only one we should ever care about.
    case PixelFormat.YCbCr_420_SP:
      // This format has never been seen in the wild, but is compatible as we
      // only care
      // about the Y channel, so allow it.
    case PixelFormat.YCbCr_422_SP:
      return new PlanarYUVLuminanceSource(data, width, height, rect.left,
          rect.top, rect.width(), rect.height());
    default:
      // The Samsung Moment incorrectly uses this variant instead of the 'sp'
      // version.
      // Fortunately, it too has all the Y data up front, so we can read it.
      if ("yuv420p".equals(previewFormatString)) {
        return new PlanarYUVLuminanceSource(data, width, height, rect.left,
            rect.top, rect.width(), rect.height());
      }
    }
    throw new IllegalArgumentException("Unsupported picture format: "
        + previewFormat + '/' + previewFormatString);
  }

  public Context getContext() {
    return context;
  }

}
